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From: Markus Elfring <Markus.Elfring@web.de>
To: Matthew Wilcox <willy@infradead.org>,
	virtualization@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [2/2] virtiofs: Improve error handling in virtio_fs_get_tree()
Date: Tue, 2 Jan 2024 17:50:31 +0100	[thread overview]
Message-ID: <a08b7922-c28d-4667-b7f3-a4064ff7d6b3@web.de> (raw)
In-Reply-To: <ZZQ5vKRcq9kkQxSD@casper.infradead.org>

>> It is probably clear that the function call “kfree(NULL)” does not perform
>> data processing which is really useful for the caller.
>> Such a call is kept in some cases because programmers did not like to invest
>> development resources for its avoidance.
>
> on the contrary, it is extremely useful for callers to not have to perform
> the NULL check themselves.

Some function calls indicate a resource allocation failure by a null pointer.
Such pointer checks are generally performed for error detection
so that appropriate exception handling can be chosen.


>                             It also mirrors userspace where free(NULL)
> is valid according to ISO/ANSI C, so eases the transition for programmers
> who are coming from userspace.  It costs nothing in the implementation
> as it is part of the check for the ZERO_PTR.

How many development efforts do you dare to spend on more complete
and efficient error/exception handling?

Regards,
Markus

  reply	other threads:[~2024-01-02 16:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-29  8:34 [PATCH 0/2] virtiofs: Adjustments for two function implementations Markus Elfring
2023-12-29  8:36 ` [PATCH 1/2] virtiofs: Improve three size determinations Markus Elfring
2024-01-02 20:41   ` Vivek Goyal
2023-12-29  8:38 ` [PATCH 2/2] virtiofs: Improve error handling in virtio_fs_get_tree() Markus Elfring
2023-12-29  8:51   ` Matthew Wilcox
2023-12-29  9:10     ` Markus Elfring
2023-12-29 14:21       ` Matthew Wilcox
2024-01-02  9:35         ` [2/2] " Markus Elfring
2024-01-02 10:17           ` Matthew Wilcox
2024-01-02 10:47             ` Markus Elfring
2024-01-02 16:28               ` Matthew Wilcox
2024-01-02 16:50                 ` Markus Elfring [this message]
2024-01-02 20:21   ` [PATCH 2/2] " Vivek Goyal

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